CN220491888U - Current sensor structure - Google Patents

Abstract

The present utility model relates to a current sensor structure. The current sensor structure includes: the packaging frame comprises a primary side and a secondary side, wherein the primary side comprises a groove penetrating through the packaging frame along a first direction, and the packaging frame further comprises a front surface and a back surface which are distributed oppositely along the first direction; the control chip is arranged on the front surface of the secondary side of the packaging frame; the Hall chip is arranged in the groove of the primary side; and the insulating film is attached to the back surface of the packaging frame and used for bearing the Hall chip. The utility model reduces the manufacturing cost of the current sensor structure and improves the accuracy and reliability of the measurement of the current sensor structure.

Description

Current sensor structure

Technical Field

The utility model relates to the technical field of integrated circuits, in particular to a current sensor structure.

Background

The current sensor structure generally includes a package frame, a control chip, and a hall chip, both of which are packaged on the package frame. Currently, two processes are mainly used to form the current sensor package structure: the method comprises the steps of directly integrating a graph structure of a Hall chip onto a control chip, and then packaging the control chip integrated with a Hall chip pattern on a packaging frame; alternatively, a single hall chip is stacked on the control chip, and then the hall chip and the control chip are packaged together on the package frame.

However, the way in which the graphic structure of the hall chip is directly integrated onto the control chip has at least the following drawbacks: firstly, professional research personnel are required to design a graph structure of the Hall chip on the control chip, the process difficulty is high, and the cost is high; secondly, at the application end, the product generates heat by the package body through high current, the control chip body is heated to generate buckling deformation, or the external stress causes the angle of the control chip to move, and the deformation and the angle movement of the control chip finally generate interference signals in the measuring process to influence the measuring accuracy; in addition, in the work of the open loop Hall sensor detection principle, the graph structure of the Hall chip is required to be infinitely close to the strongest magnetic field quantity generated by the induced current, so that the induced magnetic field quantity can be processed and converted into a voltage signal in an equal proportion, but because the graph structure of the Hall chip is directly integrated on a control chip circuit, the bottom is isolated and blocked by a circuit of the control chip and a silicon dioxide isolation material, the graph structure of the Hall chip cannot be tightly attached to a tested current lead, the strongest magnetic field quantity generated by the induced current cannot be infinitely close, and the accuracy and the reliability of a measurement result are affected. The manner in which an individual hall chip is stacked on a control chip also has at least the following drawbacks: on the one hand, the Hall chip is positioned above the control chip, so that the Hall chip cannot induce the strongest magnetic field quantity generated by current, the product performance is low, and the test requirement of high sensitivity cannot be met; on the other hand, the control chip and the Hall chip are easy to generate high-voltage breakdown.

Therefore, how to improve the accuracy and reliability of the measurement of the current sensor structure while reducing the manufacturing difficulty and cost of the current sensor structure, thereby improving the performance of the current sensor is a technical problem to be solved currently.

Disclosure of Invention

The utility model provides a current sensor structure, which is used for improving the accuracy and reliability of the measurement of the current sensor structure while reducing the manufacturing difficulty and the manufacturing cost of the current sensor structure, thereby improving the performance of the current sensor.

In order to solve the above-mentioned problems, the present utility model provides a current sensor structure including:

the packaging frame comprises a primary side and a secondary side, wherein the primary side comprises a groove penetrating through the packaging frame along a first direction, and the packaging frame further comprises a front surface and a back surface which are distributed oppositely along the first direction;

the control chip is arranged on the front surface of the secondary side of the packaging frame;

the Hall chip is arranged in the groove of the primary side;

and the insulating film is attached to the back surface of the packaging frame and used for bearing the Hall chip.

In some embodiments, the package frame further includes an isolation region between the primary side and the secondary side;

the width of the isolation region along a second direction is larger than 0.7mm, and the second direction is parallel to the front surface of the packaging frame.

In some embodiments, the hall chip is located on the surface of the insulating film, the top surface of the hall chip is lower than the top surface of the trench, and a gap is formed between the hall chip and the side wall of the trench.

In some embodiments, the trench extends along the second direction, a width of a gap between the hall chip and a sidewall of the trench along a third direction is less than or equal to 300 μm, the third direction is parallel to a front surface of the package frame, and the second direction intersects the third direction.

In some embodiments, further comprising:

and the bonding layer is at least positioned in the groove, fills up the gap between the insulating film and the Hall chip and coats the Hall chip.

In some embodiments, the grooves are located on one side of the primary side facing the secondary side, the primary side comprises a plurality of grooves which are arranged at intervals, and the hall chips are located in the grooves one by one;

the insulating film continuously covers the entire bottoms of the trenches.

In some embodiments, further comprising:

the conductive connecting wire is positioned on the packaging frame, penetrates through the isolation area along the direction of the primary side pointing to the secondary side, and one end of the conductive connecting wire is electrically connected with the Hall chip, and the other end of the conductive connecting wire is electrically connected with the control chip.

In some embodiments, the method further comprises:

and the plastic layer continuously coats the packaging frame, the Hall chip and the control chip.

In some embodiments, the insulating film is a polyimide film.

In some embodiments, the insulating film has a thickness of 25 μm to 125 μm.

According to the current sensor structure provided by the utility model, the grooves are formed in the primary side of the packaging frame, the Hall chips are placed in the grooves, and the control chips are placed in the secondary side of the packaging frame, so that the Hall chips and the control chips are mutually separated and are used as two independent structures, the manufacturing process of the Hall chips and the control chips is simplified, and the manufacturing cost of the current sensor structure is reduced. Meanwhile, the Hall chip is placed in the groove, and the insulating film for bearing the Hall chip is arranged on the back surface of the packaging frame, so that the position of the Hall chip in the groove can be limited, the Hall chip can be stably fixed in the groove, the measurement application of an isolated sensor based on an open-loop Hall principle can be realized, the test requirement of high sensitivity can be met, the measurement accuracy and reliability of the current sensor structure are improved, and the application field of the current sensor structure is enlarged. In addition, the Hall chip and the control chip are mutually separated, so that the Hall chip is not influenced when the control chip is subjected to problems such as buckling deformation caused by heating or angle deformation caused by external stress, interference signals of the current sensor structure in the measuring process are reduced, and the measuring accuracy and reliability of the current sensor structure are improved. In addition, the Hall chip is arranged in the groove of the primary side of the packaging frame, and the control chip is arranged on the secondary side of the packaging frame, so that the probability of high-voltage breakdown of the Hall chip and the control chip is reduced, and the performance stability of the current sensor structure is ensured.

Drawings

FIG. 1 is a schematic diagram of a current sensor structure in accordance with an embodiment of the present utility model;

FIG. 2 is an enlarged schematic view of the location of the dashed box in FIG. 1;

fig. 3 is a schematic structural view of a trench location in an embodiment of the present utility model.

Detailed Description

The following describes in detail the embodiments of the current sensor structure provided in the present utility model with reference to the accompanying drawings.

The present embodiment provides a current sensor structure, fig. 1 is a schematic diagram of the current sensor structure in the embodiment of the present utility model, fig. 2 is an enlarged schematic diagram of a position of a dashed frame in fig. 1, and fig. 3 is a schematic diagram of a structure of a position of a groove in the embodiment of the present utility model. As shown in fig. 1-3, the current sensor structure includes:

a package frame 10, wherein the package frame 10 comprises a primary side 16 and a secondary side 17, the primary side 16 comprises a groove 12 penetrating the package frame 10 along a first direction D1, and the package frame 10 further comprises a front surface and a back surface which are distributed oppositely along the first direction D1;

a control chip 11 mounted on the front surface of the secondary side 1 of the package frame 10;

a hall chip 13 mounted in the groove 12 of the primary side 16;

an insulating film 20 attached to the back surface of the package frame 10 for carrying the hall chip 13.

In particular, the package frame 10 may be, but is not limited to, a copper frame. The packaging machine 10 comprises the primary side 16 and the secondary side 17 which are arranged at intervals along the second direction D2, wherein the primary side 16 is the input side of the voltage, and the secondary side 17 is the output side of the voltage. In one example, the primary side 16 has a higher voltage than the secondary side 17. The control chip 11 and the hall chip 13 are both located on the front surface of the package frame 10, and the second direction D2 is parallel to the front surface of the package frame 10. The secondary side 17 includes a base island, and the control chip 11 is mounted on the base island. In an example, the control chip 11 may be, but is not limited to, an ASIC (Application Specific Integrated Circuit, integrated circuit for special applications) chip. The primary side 16 of the package frame 10 includes the groove 12 penetrating the package frame 10 along the first direction D1, the hall chip is located in the groove 12, and the first direction D1 is perpendicular to the front surface of the package frame 10. The insulating film 20 is attached to the back surface of the package frame 10, and the insulating film 20 covers at least the bottom of the trench 12 (i.e., the end of the trench 12 facing the back surface of the package frame 10), so that the insulating film 20 can carry the hall chip 13 located in the trench 12. Fig. 2 is a schematic plan view of the position of fig. 1, in which the insulating film 20 is not visible under the angle shown in fig. 2, so the position of the insulating film 20 is indicated by a broken line.

In this embodiment, the groove 12 is provided in the primary side 16 of the package frame 10, and the hall chip 13 is placed in the groove 12, and the control chip 11 is placed in the secondary side 17 of the package frame 10, so that the hall chip 13 and the control chip 11 are separated from each other and are two independent structures, so that the hall chip 13 and the control chip 11 can be formed independently, and hall chip patterns do not need to be formed in the control chip 11, thereby simplifying the manufacturing processes of the hall chip and the control chip, and reducing the manufacturing cost of the current sensor structure. Meanwhile, in this embodiment, the hall chip 13 is placed in the groove 12, and the insulating film 20 for carrying the hall chip 13 is disposed on the back of the package frame 10, so that the position of the hall chip 13 in the groove 12 can be limited, the hall chip 13 can be stably fixed in the groove, and the measurement application of the isolated sensor based on the open-loop hall principle can be realized, so that the test requirement of high sensitivity can be met, the measurement accuracy and reliability of the current sensor structure are improved, and the application field of the current sensor structure is expanded. Moreover, the bottom of the hall chip 13 is supported by the insulating film 20, and the hall chip 13 and external high voltage can be isolated, thereby reducing the probability of high voltage breakdown of the hall chip 13. The control chip 11 is arranged on the secondary side 17 with relatively low voltage, so that the probability of high-voltage breakdown of the control chip 11 can be effectively reduced. Moreover, in this embodiment, the hall chip 13 and the control chip 11 are separated from each other, so that when the control chip 11 is subjected to problems such as buckling deformation caused by heating or angular deformation caused by external stress, the hall chip 13 is not affected, interference signals of the current sensor structure in the measurement process are reduced, and accuracy and reliability of measurement of the current sensor structure are improved.

In some embodiments, the package frame 10 further includes an isolation region 18 between the primary side 16 and the secondary side 17;

the isolation region 18 has a width of greater than 0.7mm in a second direction D2, the second direction D2 being parallel to the front face of the package frame 10.

Specifically, an isolation layer is disposed in the isolation region 18, and is configured to electrically isolate the primary side 16 from the secondary side 17. In an example, the material of the isolation layer may be an insulating material such as resin. In this embodiment, the width of the plurality of isolation regions along the second direction D2 is set to be greater than 0.7mm, and insulating materials such as resin are filled in the isolation regions 18, so that the high voltage in the primary side 16 and the secondary side 17 can be better isolated, and high voltage breakdown of device structures (such as the control chip 11 and the pins) in the secondary side 17 can be avoided. In one example, the isolation layer in the isolation region 18 has a material withstand voltage greater than 15KV/mm, so that the isolation layer as a whole can withstand voltage greater than 10.5KV, thereby ensuring that the device structure in the secondary side 17 can function properly.

In some embodiments, the hall chip 13 is located on the surface of the insulating film 20, the top surface of the hall chip 13 is lower than the top surface of the trench 12, and a gap is provided between the hall chip 13 and the sidewall of the trench 12.

In some embodiments, the trench 12 extends along the second direction D2, a width of a gap between the hall chip 13 and a sidewall of the trench 12 along a third direction D3 is less than or equal to 300 μm, the third direction D3 is parallel to the front surface of the package frame 10, and the second direction D2 intersects the third direction D3. The top surface of the trench 12 refers to the surface of the trench 12 facing away from the insulating film 20. The fact that the top surface of the hall chip 13 is lower than the top surface of the trench 12 means that the hall chip 13 is integrally embedded in the trench 12, and in the first direction D1, the top surface of the hall chip 13 is lower than the front surface of the package frame 10.

Specifically, as shown in fig. 2 and 3, the groove 12 extends in the second direction D2, and the hall chip 13 is located at an end of the groove 12 toward the secondary side 17. The fact that a gap is formed between the hall chip 13 and the side wall of the groove 12 means that the hall chip 13 is not in direct contact with the groove 12, and on one hand, high voltage of the primary side 16 and the hall chip 13 can be effectively isolated; on the other hand, a space is reserved for fixing the hall chip 13 for subsequent packaging. In an example, the width of the gap between the side wall of the hall chip 13 and the side wall of the trench 12, which are distributed along the third direction D3, is greater than 0 and less than or equal to 300 μm along the third direction D3, so that the hall chip 13 can sense that the magnetic field intensity below the package frame 10 is increased while effectively isolating the high voltage of the primary side 16 from the hall chip 13, thereby further improving the measurement sensitivity of the current sensor structure.

In some embodiments, the current sensor structure further comprises:

and the bonding layer is at least positioned in the groove 12, fills the gap between the insulating film 20 and the Hall chip 13 and covers the Hall chip 13.

Specifically, the adhesive layer located in the groove 12 wraps the hall chip 13 and fills the gap between the hall chip 13 and the insulating film 20, thereby fixing the hall chip 13 to the surface of the insulating film 20, and further isolating the high voltage in the primary side 16 from the hall chip 13 through the adhesive layer. In one example, the material of the bonding layer may be an electronic adhesive. For example, the electronic adhesive may be of the type delbang 6607, SEMICOSIL 268, or SEMICOSIL 986. The material of the electronic adhesive comprises silica gel or resin, and after the electronic adhesive wraps the whole Hall chip 13, the electronic adhesive can play a role in relieving external extrusion stress and isolating external moisture to a certain extent so as to protect the Hall chip 13. In an example, the dielectric strength of the electronic adhesive is 27KV/mm, and when the width of the gap between the hall chip 13 and the sidewall of the trench 12 in the third direction D3 is 300 μm (i.e., the thickness of the electronic adhesive is 300 μm), the electronic adhesive can isolate a high voltage of 8KV, thereby effectively protecting the hall chip 13.

In some embodiments, the grooves 12 are located on one side of the primary side 16 facing the secondary side 17, and the primary side 16 includes a plurality of grooves 12 arranged at intervals, and the hall chips 13 are located in the grooves 12 one by one;

the insulating film 20 continuously covers the entire bottom of the trench 12.

Specifically, as shown in fig. 1 and 2, the primary side 16 includes a plurality of grooves 12 arranged at intervals along the third direction D3, and each of the grooves 12 is provided with one hall chip 13, so that accuracy and reliability of detection of the current sensor structure are further improved by providing a plurality of hall chips 13. The insulating film 20 also extends along the third direction D3, and the insulating film 20 father covers the bottom of all the trenches 12, so as to further simplify the manufacturing process of the current sensor structure and further improve the manufacturing efficiency of the in-store sensor structure.

In some embodiments, the current sensor structure further comprises:

the conductive connection line 14 is located on the package frame 10, the conductive connection line 14 penetrates through the isolation region 18 along the direction that the primary side 16 points to the secondary side 17, and one end of the conductive connection line 14 is electrically connected with the hall chip 13, and the other end is electrically connected with the control chip 11. In an example, one end of the conductive connection line 14 is soldered to the hall chip 13, and the other end is soldered to the control chip 11. The detection signal of the hall chip 13 is transmitted to the control chip 11 through the conductive connection wire 14, and the control signal in the control chip 11 is transmitted to the hall chip 13 through the conductive connection wire 14. In this embodiment, the length of the conductive connection line 14 can be shortened by disposing the grooves 12 and the hall chip 13 on the side of the primary side 16 facing the secondary side 17, so that the specific structure of the current sensor structure can be further simplified.

In some embodiments, the current sensor structure further comprises:

and the plastic layer continuously covers the packaging frame 10, the Hall chip 13 and the control chip 11. In an example, the material of the plastic layer may be an epoxy plastic molding compound. For example, the material model of the plastic layer can be CEL-9240HF10, CEL-9220HF13, CEL-8240HF10, EME-G600FL or EME-G700. The encapsulation frame 10, the Hall chip 13 and the control chip 11 are wrapped by the plastic layer, so that the influence of water vapor or pollutants in the external environment on the encapsulation frame 10, the Hall chip 13 and the control chip 11 is avoided, and the effects of moisture prevention and isolation are achieved.

In some embodiments, the insulating film 20 is a polyimide film.

In some embodiments, the thickness of the insulating film 20 is 25 μm to 125 μm.

In one example, the insulating film 20 has a thickness of 25 μm, 50 μm, 75 μm, 100 μm, or 125 μm. The ability of the insulating film 20 to withstand high voltage (i.e., withstand voltage value) is only related to the thickness of the insulating film 20 (e.g., the thickness of the insulating film 20 in the first direction D1), and therefore, the withstand voltage value of the insulating film 20 can be adjusted by adjusting the thickness of the insulating film 20. For example, when the thickness of the insulating film 20 made of polyimide is 25 μm, the withstand voltage value of the insulating film 20 is 6.8KV; when the thickness of the insulating film 20 made of polyimide is 75 μm, the withstand voltage value of the insulating film 20 is 11KV.

The current sensor structure may be formed by the steps of: first, the insulating film 20 is attached to the back surface of the package frame 20. Next, the hall chip 13 is placed into the groove 12 of the package frame 20 from the front surface of the package frame 20, and the hall chip 13 is placed on the insulating film 20, and the control chip 11 is placed on the island in the secondary side 17 of the package frame 20. Thereafter, the conductive connection lines 14 are formed to electrically connect the hall chip 13 and the control chip 11 through the conductive connection lines 14. Then, the hall chip 13 is wrapped with the adhesive layer, and the adhesive layer is made to fill up the gap between the hall chip 13 and the insulating film 20, and baked and cured. And then, integrally molding the packaging frame 10, the control chip 11 and the Hall chip 13 to form a plastic sealing layer for wrapping the packaging frame 10, the control chip 11 and the Hall chip 13.

According to the current sensor structure provided by the embodiment, the groove is formed in the primary side of the packaging frame, the Hall chip is placed in the groove, and the control chip is placed in the secondary side of the packaging frame, so that the Hall chip and the control chip are mutually separated and serve as two independent structures, the manufacturing process of the Hall chip and the control chip is simplified, and the manufacturing cost of the current sensor structure is reduced. Meanwhile, in the specific embodiment, the Hall chip is placed in the groove, and the insulating film for bearing the Hall chip is arranged on the back surface of the packaging frame, so that the position of the Hall chip in the groove can be limited, the Hall chip can be stably fixed in the groove, the measurement application of an isolated sensor of an open-loop Hall principle can be realized, the test requirement of high sensitivity can be met, the measurement accuracy and reliability of the current sensor structure are improved, and the application field of the current sensor structure is enlarged. In addition, the Hall chip and the control chip are mutually separated, so that the Hall chip is not influenced when the control chip is subjected to buckling deformation or external stress to cause angle deformation and the like, interference signals of the current sensor structure in the measuring process are reduced, and the measuring accuracy and reliability of the current sensor structure are improved. In addition, the Hall chip is arranged in the groove of the primary side of the packaging frame, and the control chip is arranged on the secondary side of the packaging frame, so that the probability of high-voltage breakdown of the Hall chip and the control chip is reduced, and the performance stability of the current sensor structure is ensured.

The foregoing is merely a preferred embodiment of the present utility model and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present utility model, which are intended to be comprehended within the scope of the present utility model.

Claims (7)

1. A current sensor structure, comprising:

the packaging frame comprises a primary side and a secondary side, wherein the primary side comprises a groove penetrating through the packaging frame along a first direction, and the packaging frame further comprises a front surface and a back surface which are distributed oppositely along the first direction;

the control chip is arranged on the front surface of the secondary side of the packaging frame;

the Hall chip is arranged in the groove of the primary side;

the insulating film is attached to the back surface of the packaging frame and used for bearing the Hall chip;

the packaging frame also comprises an isolation area between the primary side and the secondary side, wherein the width of the isolation area along a second direction is larger than 0.7mm, and the second direction is parallel to the front surface of the packaging frame;

the Hall chip is positioned on the surface of the insulating film, the top surface of the Hall chip is lower than the top surface of the groove, and a gap is formed between the Hall chip and the side wall of the groove;

the groove extends along the second direction, the width of a gap between the Hall chip and the side wall of the groove along a third direction is smaller than or equal to 300 mu m, the third direction is parallel to the front surface of the packaging frame, and the second direction is intersected with the third direction.

2. The current sensor structure of claim 1, further comprising:

and the bonding layer is at least positioned in the groove, fills up the gap between the insulating film and the Hall chip and coats the Hall chip.

3. The current sensor structure according to claim 1, wherein the grooves are located on one side of the primary side facing the secondary side, the primary side comprises a plurality of grooves arranged at intervals, and the hall chips are located in the grooves one by one;

the insulating film continuously covers the entire bottoms of the trenches.

4. The current sensor structure of claim 1, further comprising:

the conductive connecting wire is positioned on the packaging frame, penetrates through the isolation area along the direction of the primary side pointing to the secondary side, and one end of the conductive connecting wire is electrically connected with the Hall chip, and the other end of the conductive connecting wire is electrically connected with the control chip.

5. The current sensor structure of claim 1, further comprising:

and the plastic layer continuously coats the packaging frame, the Hall chip and the control chip.

6. The current sensor structure according to claim 1, wherein the insulating film is a polyimide film.

7. The current sensor structure according to claim 1, wherein the thickness of the insulating film is 25 μm to 125 μm.